It is important for us ____ (take) action to prevent A-Flu-HINI (甲型H1N1流感) spreading.
①爱国守法 ②热爱集体 ③明礼诚信
④团结友善 ⑤服务人民 ⑥勤俭自强 ⑦敬业奉献
△ABC的内角A,B,C的对边分别为a,b,c,已知sinB+sinA(sinC﹣cosC)=0,a=2,c= 2 ,则C=( )